Sleep apnea has been deemed a serious national health problem 31. Devices are needed to effectively screen for this disorder. As such, there is an urgent need for low cost, effective methods for evaluating and screening for sleep-related disorders 1,26. Dysfunctions such as apnea often lead to critical desaturation of brain hemoglobin and death 19, with roughly 5% of the population at risk 32. The goal of this project is to develop an inexpensive yet effective and portable instrument to be used in the evaluation of sleep apnea. Since distinctions in oxygenation are of primary importance in the diagnosis of apneic events, a new technique for non-invasively monitoring tissue oxygen levels will form the basis of this essential new device. The proposed instrument differs from currently available sleep monitoring techniques. NIR dual-wavelength, tissue oximetry monitors hemoglobin oxygenation in tissue capillary beds of the brain 2, with depths sufficient to give an effective reading of cortical desaturation. This device will afford a practical and cost-effective solution to the home monitoring problem while adding unique clinical value for application as a sleep disorder screening and monitoring device.